1. Field of the Invention
This invention concerns writing instruments and more especially reservoir pens of the kind in which ink is supplied from the reservoir chamber to the underside of a nib via a capillary channel.
2. Description of the Prior Art
A difficulty often experienced with some pens of the above kind is in dimensioning the ink feed channel to regulate the ink flow so that ink is supplied to the nib at a rate which is both enough to enable the nib to lay down a continuous line of constant width in use of the pen, and low enough to prevent ink dripping from the nib when the pen is not being used and is held with the nib pointing downwards.
To avoid problems of flooding under adverse environmental changes, it is common to provide an overflow chamber, often in the form of grooves in a feed bar which is adjacent to the nib. Excess ink from the reservoir may collect in the overflow chamber and in this way unwanted expulsion of ink from the pen is usually averted. However, the need to provide the overflow chamber inevitably complicates the pen construction and thereby increases manufacturing costs.